Moved the ScrollViewer expression animation extensions

Microsoft.Toolkit.Uwp.SampleApp/SamplePages/ScrollViewerExtensions/ScrollViewerExtensionsPage.xaml.cs

@@ -4,6 +4,8 @@
 
 using System.Collections.ObjectModel;
 using Microsoft.Toolkit.Uwp.SampleApp.Models;
+using Microsoft.Toolkit.Uwp.UI.Animations;
+using Microsoft.Toolkit.Uwp.UI.Animations.Extensions;
 using Microsoft.Toolkit.Uwp.UI.Extensions;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;

Microsoft.Toolkit.Uwp.UI.Animations/Enums/Axis.cs

@@ -22,7 +22,9 @@ namespace Microsoft.Toolkit.Uwp.UI.Animations
         /// <summary>
         /// The Z axis (depth).
         /// </summary>
-        /// <remarks>This axis might only be available in certain scenarios, such as when working with composition APIs.</remarks>
+        /// <remarks>
+        /// This axis might only be available in certain scenarios, such as when working with composition APIs.
+        /// </remarks>
         Z
     }
 }

Microsoft.Toolkit.Uwp.UI.Animations/Enums/VisualProperty.cs

@@ -4,7 +4,7 @@
 
 using Windows.UI.Composition;
 
-namespace Microsoft.Toolkit.Uwp.UI.Extensions
+namespace Microsoft.Toolkit.Uwp.UI.Animations
 {
     /// <summary>
     /// Indicates a property of a <see cref="Visual"/> object.

Microsoft.Toolkit.Uwp.UI.Animations/Extensions/ScrollViewerExtensions.cs

@@ -2,14 +2,14 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
 using System.Numerics;
+using Microsoft.Toolkit.Diagnostics;
 using Windows.UI.Composition;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Hosting;
 
-namespace Microsoft.Toolkit.Uwp.UI.Extensions
+namespace Microsoft.Toolkit.Uwp.UI.Animations.Extensions
 {
     /// <summary>
     /// Provides attached dependency properties and methods for the <see cref="ScrollViewer"/> control.
@@ -50,7 +50,6 @@ namespace Microsoft.Toolkit.Uwp.UI.Extensions
             VisualProperty property = VisualProperty.Translation)
         {
             CompositionPropertySet scrollSet = ElementCompositionPreview.GetScrollViewerManipulationPropertySet(scroller);
-
             ExpressionAnimation animation = scrollSet.Compositor.CreateExpressionAnimation($"{nameof(scroller)}.{nameof(UIElement.Translation)}.{sourceAxis}");
 
             animation.SetReferenceParameter(nameof(scroller), scrollSet);
@@ -66,7 +65,9 @@ namespace Microsoft.Toolkit.Uwp.UI.Extensions
                 case VisualProperty.Offset:
                     visual.StartAnimation($"{nameof(Visual.Offset)}.{targetAxis}", animation);
                     break;
-                default: throw new ArgumentException($"Invalid target property: {property}", nameof(property));
+                default:
+                    ThrowHelper.ThrowArgumentException("Invalid target property");
+                    break;
             }
 
             return animation;

Microsoft.Toolkit.Uwp.UI/Extensions/ScrollViewer/Enums/Axis.cs

@@ -1,22 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-namespace Microsoft.Toolkit.Uwp.UI.Extensions
-{
-    /// <summary>
-    /// Indicates an axis in the 2D space
-    /// </summary>
-    public enum Axis
-    {
-        /// <summary>
-        /// The X axis (horizontal)
-        /// </summary>
-        X,
-
-        /// <summary>
-        /// The Y axis (vertical)
-        /// </summary>
-        Y
-    }
-}